1. Field of the Invention
The present invention relates to an analysis apparatus and method of analyzing an image to count the number of passing objects.
2. Description of the Related Art
Counting persons or vehicles going along a road or passing through the doorway of a store has become prevalent. Detailed counting methods include, for example, visually counting using a tally counter, and counting by combining an infrared sensor and counting software on a personal computer (PC). Also widely conducted are capturing a store or a road by a surveillance camera and recording an image. When the captured image is analyzed by a camera or a recording apparatus, and persons or vehicles passing on the image are counted, the cost is low, and any other equipment is not necessary.
In surveillance cameras, parameters such as the angle of view and the capturing direction are fixed or variable. A surveillance camera having variable parameters can cyclically capture a wide range, capture an enlarged image of a portion where an abnormality has occurred, or track and capture a suspicious person. However, the advantages of the surveillance camera with variable parameters hinder counting the number of passing objects. That is, if a passing person or vehicle is located outside the capturing range, it cannot be counted. Even within the capturing range, if the angle or magnification changes, the image analysis condition changes, and a predetermined counting accuracy cannot be obtained.
To prevent this, for example, Japanese Patent Laid-Open No. 2005-141695 discloses a monitor system that prohibits the operator from changing parameters during counting. This patent literature also discloses a monitor system that causes the operator to select whether to interrupt counting if a parameter change operation has been done during counting. When the operator selects to interrupt, the counting is interrupted.
However, a parameter change operation for, for example, causing a surveillance camera to capture an enlarged image of a portion where an abnormality has occurred is often highly urgent. Hence, when the operator is selecting whether to interrupt, the system may fail in capturing an important object at a sufficient angle of view. For this reason, an operation of changing a parameter such as an angle of view needs to be immediately executable independently of the counting state.
The parameter operation is performed at the expense of counting accuracy, as described above. However, if the frequency of counting interrupt by the parameter operation in case of abnormality occurrence is low, correct counting can be performed during most of the time. Hence, the task is how to handle the result of correct counting.